I liked the rolling plane set in Warbirds, but I think it was certainly one factor in the decline in popularity of that sim. It didn't appeal to all tastes and all skill levels (I personally found it a real challenge to fly those early-war aircraft, but for many people challenge is not what it's all about, and that needs to be recognized, much as I don't personally approach the game with that mentality). So I think no RPS in the MA.
I also don't think it should be implemented in the CT. The kind of specialized scenarios that are being offered now are great, and offer a lot of variety in terms of what you are forced to fly.
As the customer base grows, it may be possible down the line to envision another arena (and this may not be very far off), which features a combination of an RPS, no-icon environment, and no killshooter. Given how sparsely attended the CT is at times, however, I just feel the sim needs to grow a little bit more in order to achieve a critical mass for anything else other than the MA. The continuing success of this sim is going to be founded on two interrelated things: growth, and choice. And, again, much as I really like RPS, it presents an inolerable restriction for too many people for it to really work in anything more than a specialized context.